A new Stargate team embarks on a dangerous mission to a distant galaxy, where they discover a mythical lost city -- and a deadly new enemy.

After a series of run-ins with the Wraith, the team begins to suspect their Athosian allies of having a spy in their midst.

Sheppard and the team visit a world where no one is over 24 years old -- because of a ritual suicide practice they believe keeps the Wraith at bay.

When a massive storm threatens the city, Atlantis is evacuated -- only to be taken over by the team's newest enemy.

Sheppard's team investigates a downed Wraith ship, and find themselves stuck on a planet with a lone Wraith survivor.

A woman is found in suspended animation in Atlantis, and the team is shocked to see that it is Dr. Weir herself, who tells them of her trip 10,000 years into the city's past.